Endoscopic multiple sample bioptome with enhanced biting action

ABSTRACT

An endoscopic multiple sample bioptome includes a hollow outer member and an axially displaceable inner member extending therethrough. The proximal ends of the outer and inner members are coupled to an actuator for axially displacing one relative to the other. The distal end of the outer member is coupled to one of a cylinder having a sharp distal edge and a jaw assembly, while the distal end of the inner member is coupled to the other. The jaw assembly includes a pair of opposed, preferably toothed jaw cups each of which is coupled by a resilient arm to a base member. The arms are bent to lie in planes which intersect the axis of the base member and to locate the jaws apart from each other. The base member is mounted inside the cylinder and axial movement of the jaw assembly and cylinder relative to each other draws the arms into the cylinder and brings the jaw cups together in a biting action. The biting action is enhanced according to the invention by arranging the cutting edge of each jaw to lie in a plane which intersects the plane in which the distal portion of the jaw arm lies. The biting action is further enhanced by providing a closing cam on the outer surface of the jaws which is engaged by the cylinder when the jaws are closed. The arrangement of the cutting edges also presents a smooth surface to the interior of an endoscope and the closing cams prevent the sleeve from sliding completely over and off of the jaws.

This application is a continuation-in-part of application Ser. No.08/189,937 filed Feb. 1, 1994 now U.S. Pat. No. 5,542,432 which is acontinuation-in-part of Ser. No. 837,046, filed Feb. 18, 1992 now U.S.Pat. No. 5,507,296, which are hereby incorporated by reference herein inits entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to endoscopic surgical instruments. Moreparticularly, this invention relates to an instrument for takingmultiple biopsy tissue samples.

2. State of the Art

Endoscopic biopsy procedures are typically performed with an endoscopeand an endoscopic biopsy forceps device (bioptome). The endoscope is along flexible tube carrying fiber optics and having a narrow lumenthrough which the bioptome is inserted. The bioptome typically includesa long flexible coil having a pair of opposed jaws at the distal end andmanual actuation means at the proximal end. Manipulation of theactuation means opens and closes the jaws. During a biopsy tissuesampling operation, the surgeon guides the endoscope to the biopsy sitewhile viewing the biopsy site through the fiber optics of the endoscope.The bioptome is inserted through the narrow lumen of the endoscope untilthe opposed jaws arrive at the biopsy site. While viewing the biopsysite through the fiber optics of the endoscope, the surgeon positionsthe jaws around a tissue to be sampled and manipulates the actuationmeans so that the jaws close around the tissue. A sample of the tissueis then cut and/or torn away from the biopsy site while it is trappedbetween the jaws of the bioptome. Keeping the jaws closed, the surgeonwithdraws the bioptome from the endoscope and then opens the jaws tocollect the biopsy tissue sample.

A biopsy tissue sampling procedure often requires the taking of severaltissue samples either from the same or from different biopsy sites.Unfortunately, most bioptomes are limited to taking a single tissuesample, after which the device must be withdrawn from the endoscope andthe tissue collected before the device can be used again to take asecond tissue sample. The single-sample limitation of most bioptomes isdue to the limited space between the biopsy forceps jaws. Severalattempts have been made to provide an instrument which will allow thetaking of several tissue samples before the instrument must be withdrawnand the samples collected. Problems in providing such an instrumentinclude the extremely small size required by the narrow lumen of theendoscope and the fact that the instrument must be flexible in order tobe inserted through the lumen of the endoscope. Thus, several knownmultiple sample biopsy instruments are precluded from use with anendoscope because of their size and rigidity. These include the "punchand suction type" instruments disclosed in U.S. Pat. No. 3,989,033 toHalpern et al. and U.S. Pat. No. 4,522,206 to Whipple et al. Both ofthese devices have a hollow tube with a punch at the distal end and avacuum source coupled to the proximal end. A tissue sample is cut withthe punch and suctioned away from the biopsy site through the hollowtube. It is generally recognized, however, that suctioning tissuesamples through a long narrow flexible bioptome is virtually impossible.

Efforts have been made to provide a multiple sampling ability to aninstrument which must traverse the narrow lumen of an endoscope. Theseefforts have concentrated on providing a cylindrical storage space atthe distal end of the instrument wherein several tissue samples can beaccumulated before the instrument is withdrawn from the endoscope. U.S.Pat. No. 4,651,753 to Lifton, for example, discloses a rigid cylindricalmember attached to the distal end of a first flexible tube. Thecylindrical member has a lateral opening and a concentric cylindricalknife blade is slidably mounted within the cylindrical member. A secondflexible tube, concentric to the first tube is coupled to the knifeblade for moving the knife blade relative to the lateral opening in thecylindrical member. A third flexible tube having a plunger tip ismounted within the second flexible tube and a vacuum source (a syringe)is coupled to the proximal end of the third tube. A tissue sample istaken by bringing the lateral opening of the cylindrical member upon thebiopsy site, applying vacuum with the syringe to draw tissue into thelateral opening, and pushing the second flexible tube forward to movethe knife blade across the lateral opening. A tissue sample is therebycut and trapped inside the cylindrical knife within the cylindricalmember. The third flexible tube is then pushed forward moving itsplunger end against the tissue sample and pushing it forward into acylindrical storage space at the distal end of the cylindrical member.Approximately six samples can be stored in the cylindrical member, afterwhich the instrument is withdrawn from the endoscope. A distal plug onthe cylindrical member is removed and the six samples are collected bypushing the third tube so that its plunger end ejects the samples.

The device of the Lifton patent suffers from several recognizabledrawbacks. First, it is often difficult to obtain a tissue samplelaterally of the device. Second, in order to expedite the obtaining of alateral sample, a syringe is used to help draw the tissue into thelateral opening. However, this causes what was once a two-step procedure(position and cut), to become a three-step procedure (position, suction,cut). In addition, the use of a syringe requires an additional hand.Third, the Lifton patent adds a fourth step to the biopsy procedure byrequiring that the tissue sample be pushed into the storage space. Thus,in all, the Lifton patent requires substantial effort on the part of thesurgeon and an assistant and much of this effort is involved in pushingtubes, an action which is counter-intuitive to classical biopsysampling. The preferred mode of operation of virtually all endoscopictools is that a gripping action at the distal end of the instrument iseffected by a similar action at the proximal end of the instrument.Classical biopsy forceps jaws are closed by squeezing a manual actuationmember in a syringe-like manner.

A more convenient endoscopic multiple sample biopsy device is disclosedin U.S. Pat. No. 5,171,255 to Rydell. Rydell provides a flexibleendoscopic instrument with a knife-sharp cutting cylinder at its distalend. A coaxial anvil is coupled to a pull wire and is actuated in thesame manner as conventional biopsy forceps. When the anvil is dram intothe cylinder, tissue located between the anvil and the cylinder is cutand pushed into a storage space within the cylinder. Several samples maybe taken and held in the storage space before the device is withdrawfrom the endoscope. While the device of Rydell is effective in providinga multiple sample tool where each sample is obtained with a traditionaltwo-step procedure (position and cut), it is still limited to lateralcutting which is often problematic. Traditional biopsy forceps providejaws which can grasp tissue frontally or laterally. Even as such, it isdifficult to position the jaws about the tissue to be sampled. Lateralsampling is even more difficult.

Parent application Ser. No. 08/189,937 discloses an endoscopic multiplesample bioptome having a hollow outer member and an axially displaceableinner member extending therethrough. The proximal ends of the outer andinner members are coupled to an actuator for axially displacing onerelative to the other. The distal end of the outer member is coupled toone of a cylinder having a sharp distal edge and a jaw assembly, whilethe distal end of the inner member is coupled to the other. The jawassembly includes a pair of opposed, preferably toothed, jaw cups eachof which is coupled by a resilient arm to a base member. The resilientarms are bent to urge the jaws away from each other. The base member ismounted inside the cylinder and axial movement of the jaw assembly andcylinder relative to each other draws the resilient arms into thecylinder and brings the jaw cups together in a biting action. Dependingon the geometry of the resilient arms, however, when the cylinder ismoved over the arms, they may tend to bow inward and prevent a completeclosing of the jaws. This results in a less than optimal biting action.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an endoscopicmultiple sample bioptome which is not limited to lateral tissuesampling.

It is also an object of the invention to provide an endoscopic multiplesample bioptome which is easy to operate.

It is another object of the invention to provide an endoscopic multiplesample bioptome which is inexpensive to manufacture.

It is still another object of the invention to provide an endoscopicmultiple sample bioptome which has all of the advantages of traditionalbiopsy forceps with the added ability to collect multiple samples.

It is yet another object of the invention to provide an endoscopicbioptome with jaws which completely close.

It is still another object of the invention to provide an endoscopicbioptome which has an enhanced biting action.

In accord with these objects which will be discussed in detail below,the endoscopic bioptome of the present invention includes a relativelylong flexible member having a lumen with an axially displaceable wireextending therethrough. The proximal ends of the flexible member andwire are coupled to a manual actuation means for axially displacing oneof the flexible member and wire relative to the other. The distal end ofthe flexible member is coupled to a jaw assembly. The distal end of thewire is coupled to a cylinder which is slidable over the jaw assembly.The jaw assembly includes a pair of opposed jaw cups, each of which iscoupled by a narrow arm to a base member and each of which has a sharpcutting edge. The narrow arm of each jaw is a resilient member whichincludes a portion which is bent away from the longitudinal axis of thecylinder in order to locate the jaw cups substantially apart from eachother. The base member of the jaw assembly is mounted inside thecylinder and axial movement of one of the jaw assembly and cylinderrelative to the other draws the arms of the jaws into the cylinder ormoves the cylinder over the arms of the jaws to bring the jaw cupstogether in a biting action. In order to assure that the jaws completelyclose together in a biting action, the jaw cups are provided with aclosing cam. The closing cam is preferably a ramped surface on the outersurface of the jaw cup which is engaged by the cylinder to move the jawcup further closed. In addition to encouraging a complete closing of thejaw cups, the closing cams also prevent the cylinder from moving too fardistally over the jaw cups. To further encourage a complete closing,each jaw cups is preferably provided with a cutting edge which lies in aplane which intersects the plane in which the bent portion of the jawarm lies. In addition to encouraging a complete closing of the jaw cups,the arrangement of the cutting edge in this way provides a smootherouter surface of the closed jaws which is well tolerated by the interiorof an endoscope.

Additional objects and advantages of the invention will become apparentto those skilled in the art upon reference to the detailed descriptiontaken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view in partial section of the proximal endof a first embodiment of the invention;

FIG. 2 is an enlarged partially transparent side elevation view of thedistal end of a first embodiment of the invention with the jaws open;

FIG. 3 is an enlarged transparent top view of the distal end of anembodiment of the invention;

FIG. 4 is a view similar to FIG. 2, but with the jaws closed;

FIG. 5 is a schematic view of a first jaw assembly in the open position.

FIG. 5a is a schematic view of the jaw assembly of FIG. 5 in the closedposition;

FIG. 6 is a schematic view of a second jaw assembly in the openposition;

FIG. 6a is a schematic view of the jaw assembly of FIG. 6 in the closedposition;

FIG. 7 is a schematic view of a second embodiment of a jaw assemblyaccording to the invention in the open position; and

FIG. 7a is a schematic view of the jaw assembly of FIG. 7 in the closedposition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1 through 4, a first embodiment of the multiplesample bioptome 10 includes a proximal handle 12 and a distal endeffector 14. A long flexible coil 16 having an axially displaceablecontrol wire 18 extending therethrough couples the handle 12 and the endeffector 14. The coil 16 is preferably covered with a PTFE, FEP orpolyolefin sheath 15 along substantially all of its length and a strainrelief sleeve 17 covering a portion of the coil which extends from thehandle 12. The control wire 18 is preferably flexible but longitudinallyinelastic and is ideally formed from 304 Steel and provided with andouter diameter of approximately 0.018 inch. The proximal handle 12includes a central shaft 20 and a displaceable spool 22. The proximalend of the shaft 20 is provided with a thumb ring 24 and a longitudinalbore 26 is provided at the distal end of the shaft 20. A longitudinalslot 28 extends from the proximal end of bore 26 to a point distal ofthe thumb ring 24. The displaceable spool 22 is provided with a crossmember 30 which passes through the slot 28 in the central shaft 20. Thecross member 30 is provided with a central through hole 32 and aradially engaging set screw 34. According to the first embodiment of theinvention, a short bore 36 and a radially engaging set screw 38 areprovided in the shaft 20 distal of the thumb ring 24 with the bore 36communicating with the longitudinal slot 28. In the first embodiment ofthe invention, the proximal end of the coil 16 extends into the centralthrough hole 32 in the cross member 30 and is fixed there by the setscrew 34. The proximal end of the control wire 18, passes through slot28, is inserted into the short bore 36, and held there by the set screw38. From the foregoing, those skilled in the art will appreciate thatrelative movement of the shaft 20 and spool 22 results in movement ofthe control wire 18 relative to the coil 16. Such action results inactuation of the end effector 14 as described in detail below.

Turning now to FIGS. 2 through 4, the end effector 14 includes acylindrical sleeve 40 (preferably having a knife-sharp distal edge 42)and a jaw assembly 44. The jaw assembly 44 includes a pair of opposedjaw cups 46a, 46b each preferably having a plurality of sharp, radiallyarranged teeth 48a, 48b. A resilient, preferably narrow, arm 50a, 50bextends proximally from each jaw cup 46a, 46b. A cylindrical base member52 joins the proximal ends of the arms 50a, 50b. As seen best in FIG. 2,the narrow resilient arms 50a, 50b are bent apart from each other at apoint 51a, 51b between the cylindrical base member 52 and the respectivejaw cups 46a, 46b, thereby locating the jaw cups 46a, 46b apart fromeach other and placing the distal portion of each arm in a plane whichintersects the axis of the base member. The cylindrical base member 52is coupled to the distal end of the flexible coil 16 by welding,soldering, crimping, or any other suitable manner. The cylindricalsleeve 40 is coupled to the distal end of the control wire 18 byproviding the sleeve 40 with a lateral hole 45 which engages a bent end18a of the control wire 18. As shown in FIGS. 2 through 4, the bent end18a of the control wire 18 is welded to the hole 45 in the side of thesleeve 40. However, as described in detail in the parent application,other methods of coupling the control wire to the sleeve are possible.The cylindrical sleeve 40 is slidably mounted over the cylindrical basemember 52 as shown in FIGS. 2 and 3 and is axially movable over theresilient arms 50a, 50b as shown in FIG. 4.

According to the invention, the jaw cups 46a, 46b are preferably eachprovided with a closing cam 47a, 47b on their outer surface. Eachclosing cam is preferably an inclined bump which rises from the surfaceof the jaw cup in the distal direction. In addition, the teeth 48a, 48b(i.e., the top points or valleys) on each jaw cup are preferablyarranged in a plane which is angled relative to the plane of the bentportion of the arm so that the respective teeth fully engage each otherwhen the jaws are closed as shown in FIG. 4 and discussed below in moredetail with reference to FIGS. 5-7.

As seen in FIG. 3, the jaw cups 46a, 46b have an eccentric cross sectionwith their widest point indicated by the line 49. Distal of the line 49the jaw cups are substantially hemispherical, and proximal of the line49 the jaw cups are substantially hemi-elliptical. The closing cams orramps 47a, 47b are preferably located proximal of the widest portions ofthe jaws, i.e., proximal of the line 49. It will also be seen that theside walls of the jaw cups 46a, 46b taper towards the arms 50a, 50b toprovide a smooth transition from the jaw cups to the arms.

From the foregoing description and with reference to FIGS. 1 through 4,those skilled in the art will appreciate that when the spool 22 and theshaft 20 are axially displaced relative to each other, the cylindricalsleeve 40 and the jaw assembly 44 are similarly axially displacedrelative to each other, from the positions shown in FIG. 2 to thepositions shown in FIG. 4 and vice versa. It will also be appreciatedthat when the spool 22 and shaft 20 are in the approximate positionshown in FIG. 1, the cylindrical sleeve 40 and the jaw assembly 44 willbe in the approximate position shown in FIG. 2; i.e., with the jawsopen. Thus, those skilled in the art will further appreciate that whenthe spool 22 is moved towards the thumb ring 24, or vice versa, thecylindrical sleeve 40 and the jaw assembly 44 will be brought into theapproximate position shown in FIG. 4; i.e., with the jaws closed.Moreover, it will also be appreciated that it is preferable to move thethumb ring 24 relative to the spool 22, rather than vice versa sincethat will move the cylindrical sleeve 40 relative to the jaw assembly 44rather than vice versa. This is desirable so that the jaw assembly isnot moved away from a tissue sample while the jaws are being closed. Ineither case, as the arms 50a, 50b are drawn together by the cylindricalsleeve 40, the arms tend to flex at their coupling to the cylindricalbase member 52, as seen in FIG. 4, rather than at their respective bends51a, 51b. This geometry of the arms is compensated for by a specialarrangement of the teeth of the jaws which will be understood from thefollowing discussion.

Referring now to FIGS. 5 and 5a, a jaw assembly 101 which includes afirst jaw cup 102a and a second jaw cup 102b. Each of the jaw cups 102a,102b are coupled by a respective resilient arm 103a, 103b to acylindrical base member 104. The arms 103a, 103b are bent away from eachother (away from the longitudinal axis of the base member) at the points104a, 104b where they meet the base member 104. The jaw cups 102a, 102bare each provided with a cutting edge 105a, 105b, which may include anarray of teeth or which may simply be a sharp edge. When the sleeve (notshown) is moved over the jaw assembly, the arms 103a, 103b are flexed atthe points 104a, 104b and the jaws 102a, 102b are brought together asshown in FIG. 5a so that their cutting edges engage each other. Thoseskilled in the art will appreciate that in this arrangement, the arms103a, 103b are moved into a position where they are substantiallyparallel when the jaws are closed. Therefore, the cutting edge of eachjaw should be arranged so that it lies in a plane which is substantiallyparallel to the arm of the jaw.

Referring back to FIGS. 2-4, it will be appreciated that, due to thegeometry of the end effector 14 and its coupling with the coil 16 andthe pull wire 18, it is difficult to provide the necessary bends 51a,51b in the jaw arms 50a, 50b at the point where they meet the basemember 52. This is because a certain amount of space is required betweenthe base member and the arm bends to accommodate the coupling (18a, 45)of the pull wire 18 with the cylindrical sleeve 40.

Turning now to FIGS. 6 and 6a, the same jaw assembly 101 as describedabove, is provided with bends 104'a and 104'b in its arms 103a, 103b atpoints distal of the cylindrical base member 104. Despite the locationof these bends, the resiliency of the arms will cause them to flex attheir connection to the base member 104 when the sleeve (not shown) ismoved over the jaw assembly. When the arms 103a, 103b flex as shown inFIG. 6a, the jaw cups 102a, 102b are brought together, but their cuttingedges 105a, 105b do not completely engage. This is because the cuttingedges 105a, 105b are arranged to lie in a plane which is substantiallyparallel to distal portion of the arms 103a, 103b, and the arms 103a,103b are never brought into parallel alignment, due to the bends 104'a,104'b. The failure of the cutting edges to fully engage results in twodisadvantages: an incomplete cutting action, and exposed sharp edgeswhich can damage the interior of an endoscope. Therefore, in order toprovide for the complete engagement of the cutting edges of the jaws,the geometry of the cutting edges must be altered.

FIGS. 7 and 7a show a jaw assembly 144 according to the invention. Thejaw assembly 144 includes a first jaw cup 146a and a second jaw cup146b. Each of the jaw cups are coupled by a respective resilient arm150a, 150b to a cylindrical base member 152. The arms are bent away fromeach other (and away from the longitudinal axis of the base member) atpoints 151a, 151b which are distal of the base member 152. The jaw cups146a, 146b are each provided with a cutting edge 148a, 148b which isarranged to lie in a plane which is not parallel to the distal (bentaway) portion of the respective arm 150a, 150b. In particular, each ofthe cutting edges is arranged to lie in a plane which intersects theplane in which the distal portion of the jaw arm lies. When the sleeve(not shown) is moved over the jaw assembly, the arms 150a, 150b flex attheir connection to the base member 152 and the jaws 146a, 146b arebrought together as shown in FIG. 7a so that their cutting edges 148a,148b substantially completely engage each other.

Referring once again to FIGS. 2 and 4, it will be appreciated that thejaw assembly 44 is provided with cutting teeth 48a, 48b arranged in aplane as just described to achieve a substantially complete intermeshingof the teeth when the jaws are closed. It will further be appreciatedthat the closing cams 47a, 47b further encourage a complete meshing ofjaw teeth particularly in the distal portion of the jaws. The closingcams further prevent the sleeve 40 from moving too far distally over thejaw cups. This is an important safety advantage in case the sleeve 40should become disengaged from the pull wire 18, as the closing cams willprevent the sleeve from falling off the bioptome and becoming lostinside the body of the patient.

Those skilled in the art will appreciate that the bioptome according tothe present invention is used in substantially the same way as explainedin the parent application which was previously incorporated herein byreference. The instant bioptome, however, has an enhanced biting action.Like the bioptome of the parent application, the jaw assembly may becoupled to the pull wire and the cylindrical sleeve coupled to the coil,rather than vice versa, and the couplings may be effected in severaldifferent ways. Several different types of actuating means (e.g.,scissors grip) may be used other than the spool and thumb ringarrangement shown herein. The jaws may be manufactured by severalmethods including stamping, laser cutting, etc. In the presentlypreferred embodiment, the jaws are formed as flat blanks from a sheet of410 stainless steel using a die and punch. The formed blanks are placedin a die having a concave surface corresponding to the outer surface ofthe jaw cups and an indentation in the concave surface corresponding tothe closing cam. A punch having a convex surface corresponding to theinterior surface of the jaw cups and a raised bump corresponding to aninterior of the closing cam is pressed onto the flat blank and the jawcup is cold formed from the flat blank.

There have been described and illustrated herein several embodiments ofan endoscopic multiple sample bioptome. While particular embodiments ofthe invention have been described, it is not intended that the inventionbe limited thereto, as it is intended that the invention be as broad inscope as the art will allow and that the specification be read likewise.Thus, while particular configurations of the cutting edges of the jaws,it will be appreciated that other types of cutting edges could beutilized. In particular, the cutting edges may have teeth or a toothlesssharp edge, or a combination of both. The teeth may be radially arrangedor arranged in another manner. Also, while the distal end of thecylindrical sleeve has been shown and described as having a knife-sharpedge, a sleeve without a sharp edge could also be used with theinventive jaw assembly. Moreover, while particular configurations havebeen disclosed in reference to the closing cams, it will be appreciatedthat other configurations could be used as well. For example, ratherthan have closing cams ramping outwardly from the surface of the jaws,the jaws themselves may be arranged to increase in diameter such thatthe outer diameter of the closed jaw cups where the cam would otherwisebe located is larger than the inner diameter of the cylinder. In otherwords, the jaw cups may be arranged to take on a bulbous form in orderto expedite closing of the cups by the cylinder and prevent the cylinderfrom passing over the jaws. Furthermore, it will be appreciated thatwhile the invention was described as advantageously permitting theobtaining of multiple biopsies without removal from the surgical site,the apparatus of the invention, if desired, could still be used forobtaining single biopsies at a time. It will therefore be appreciated bythose skilled in the art that yet other modifications could be made tothe provided invention without deviating from its spirit and scope as soclaimed.

We claim:
 1. An endoscopic bioptome, comprising:a) a hollow outer memberhaving a proximal and a distal end; b) an inner control member having aproximal and a distal end and extending through said hollow outermember; c) a cylinder having a longitudinal axis and a sharp distaledge, said cylinder being coupled to said distal end of one of saidhollow outer member and said inner control member; d) a jaw assemblyincluding a base member and a pair of resilient arms extending distallyfrom said base member, each of said resilient arms terminating in a jawcup having a cutting edge, each of said resilient arms having a portionbeing bent away from said longitudinal axis of said cylinder, said basemember being coupled to said distal end of the other of said hollowouter member and said inner control member; and e) actuation meanscoupled to said proximal end of said hollow outer member and to saidproximal end of said inner control member for axially displacing one ofsaid hollow outer member and said inner control member relative to theother of said hollow outer member and said inner control member, suchthat said cylinder extends around said pair of resilient arms, closessaid jaws, and cuts tissue grasped by said jaw assembly wherein,each ofsaid respective cutting edges of said jaw cups lies in a plane whichintersects a plane in which said portion of the respective resilient armwhich is bent away from said longitudinal axis of said cylinder lies. 2.An endoscopic bioptome according to claim 1, wherein:at least one ofsaid jaw cups has an outer surface which is arranged to prevent saidcylinder from extending completely over said jaw cups when said jaw cupsare closed.
 3. An endoscopic bioptome according to claim 2, wherein:atleast one of said outer surfaces of said jaw cups includes a ramp whichis engaged by said cylinder when said jaw cups are closed.
 4. Anendoscopic bioptome according to claim 3, wherein:each of said outersurfaces of said jaw cups includes a ramp, each of said ramps is aclosing cam, and each of said jaw cups has an inner surface definingsaid cutting edge.
 5. An endoscopic bioptome according to claim 1,wherein:each of said portions of said resilient arms is bent away fromsaid longitudinal axis of said cylinder at a point distal of said basemember, and a proximal portion of each of said resilient arms lies in aplane which is substantially parallel to said longitudinal axis of saidcylinder.
 6. A jaw assembly for use in an endoscopic bioptome,comprising:a) a base member having a longitudinal axis; and b) a pair ofresilient arms extending distally from said base member, each of saidresilient arms having a portion being bent away from said longitudinalaxis of said base member and lying in a plane which intersects saidlongitudinal axis of said base member, and each of said resilient armsterminating in a jaw cup having a cutting edge which lies in a planewhich intersects the plane in which the resilient arm lies and at leastone of said jaw cups is provided with a closing ramp.
 7. A jaw assemblyaccording to claim 6, wherein:said jaw cups are provided with a portionof increasing outer diameter when closed.
 8. A jaw assembly according toclaim 7, wherein:said closing ramp is a closing cam.
 9. A jaw assemblyaccording to claim 8, wherein:both of said jaw cups are provided withclosing cams, and each of said jaw cups has an outer surface and aninner surface defining said cutting edge, and said closing cam is aninclined ramp on said outer surface.
 10. A jaw assembly according toclaim 6, wherein:each of said resilient arm portions is bent away fromsaid longitudinal axis of said base member at a point distal of saidbase member, and a proximal portion of each of said resilient arms liesin a plane which is substantially parallel to said longitudinal axis ofsaid base member.